Polyamide, polyamide compositions, polyimide, polyimide films, laminates, methods for manufacturing laminates, and electronic devices thereof.

Abstract

The polyamide of this invention has a tetracarboxylic dianhydride residue and a diamine residue. The tetracarboxylic dianhydride residue comprises one or more residues selected from the group consisting of 3,3',4,4'-biphenyltetracarboxylic dianhydride residues, 9,9-bis(3,4-dicarboxyphenyl)furan dianhydride residues, 4,4'-oxophthalic anhydride residues, and spiro[11H-difurano[3,4-b:3',4'-i][11H]furan]-1,3,7,9-tetraone residues, as well as a 2,3,6,7-naphthalenetetracarboxylic dianhydride residue. The diamine residue comprises a 2,2'-bis(trifluoromethyl)benzidine residue. The content of the 2,3,6,7-naphthalenetetracarboxylic dianhydride residue is 5 mol% to 90 mol%. The content of the 2,2'-bis(trifluoromethyl)benzidine residue is 50 mol% or more.

Description

Technical Field

[0001] This invention relates to polyamide, polyamide compositions, polyimide, polyimide films, laminates, methods for manufacturing laminates, and electronic devices. Furthermore, this invention relates to electronic device materials using polyimide, thin-film transistor (TFT) substrates, flexible display substrates, color filters, printed materials, optical materials, image display devices (more specifically, liquid crystal displays, organic EL (electroluminescence), electronic paper, etc.), 3D displays, solar cells, touch panels, transparent conductive film substrates, and alternative materials to currently used glass components. Prior Technology

[0002] With the rapid development of displays such as liquid crystal displays (LCDs), organic EL displays (OLEDs), and electronic paper displays, as well as electronic devices such as solar cells and touch panels, there is a continuous trend towards thinner, lighter, and more flexible devices. In these devices, polyimide is used instead of glass substrates as the substrate material.

[0003] In these devices, various electronic components, such as thin-film transistors or transparent electrodes, are formed on a substrate. The formation of these electronic components requires a high-temperature process. Polyimide has sufficient heat resistance to withstand high-temperature processes, and its coefficient of thermal expansion (CTE) is close to that of glass substrates or electronic components. Therefore, it is not prone to internal stress and is suitable as a substrate material for flexible displays, etc.

[0004] Generally, aromatic polyimides are colored yellowish-brown due to the formation of intramolecular conjugation or charge transfer (CT) complexes. However, since light is extracted from the opposite side of the substrate in top-emitting organic ELs and the like, the substrate is not required to be transparent, and the previous aromatic polyimides have been used. However, in cases where light emitted from the display element passes through the substrate and exits, such as in transparent displays, bottom-emitting organic ELs, and liquid crystal displays, or when sensors or camera modules are placed on the back of the substrate to make smartphones into full-screen displays (notchless), the substrate is required to have higher optical properties (more specifically, transparency, etc.).

[0005] Against this backdrop, there is a need for a material that possesses the same heat resistance as existing aromatic polyimides, while exhibiting reduced coloring and excellent transparency.

[0006] It is known that techniques exist for using aliphatic monomers to suppress the formation of CT complexes in order to reduce the coloration of polyimides (Patent Documents 1 and 2), and techniques exist for improving transparency by using monomers with fluorine atoms (Patent Document 3). Furthermore, in order to obtain polyimides with low CTE, polyimides with a naphthalene backbone having higher planarity have been studied (Patent Document 4). [Previous Technical Documents] [Patent Literature]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2016-29177 [Patent Document 2] Japanese Patent Application Publication No. 2012-41530 [Patent Document 3] Japanese Patent Application Publication No. 2014-70139 [Patent Document 4] International Publication No. 2016 / 166961 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] Although the polyimide described in Patent Documents 1 and 2 has high transparency and low CTE, it has a low thermal decomposition temperature due to its aliphatic structure, making it difficult to apply to high-temperature processes in the formation of electronic components.

[0010] Furthermore, in applications requiring transparency, from the viewpoint of color reproduction, a higher transmittance of blue light (light with a wavelength around 470 nm) is particularly desirable, and practically, a higher transmittance of light with a wavelength of 400 nm is required. According to the inventor's research, the transmittance of polyimide with a wavelength of 400 nm described in Patent Documents 3 and 4 is relatively low.

[0011] Using the techniques described in Patent Documents 1-4, it is difficult to obtain polyimide with excellent heat resistance and high transmittance of light with a wavelength of 400 nm.

[0012] This invention was made in view of the above-mentioned actual situation, and its object is to provide a polyimide with excellent heat resistance and high transmittance of light at a wavelength of 400 nm, and polyacrylic acid as its precursor. Furthermore, this invention also aims to provide an article or component requiring heat resistance and transparency manufactured using this polyimide and polyacrylic acid. In particular, this invention aims to provide an article or component having the polyimide film of this invention formed on the surface of inorganic materials such as glass, metal, metal oxides, and single-crystal silicon. [Technical means to solve the problem]

[0013] <State of the Invention> The present invention includes the following states.

[0014] [1] A polyamide having a tetracarboxylic dianhydride residue and a diamine residue, and The aforementioned tetracarboxylic dianhydride residues include those selected from 3,3',4,4'-biphenyltetracarboxylic dianhydride residues, 9,9-bis(3,4-dicarboxyphenyl)furan dianhydride residues, 4,4'-oxophthalic anhydride residues, and spiro[11H-difurano[3,4-b:3',4'-i]𠮿 One or more residues from the group consisting of -11,9'-[9H][-1,3,7,9-tetraone residues, and 2,3,6,7-naphthalenetetracarboxylic acid dianhydride residues. The diamine residues mentioned above include 2,2'-bis(trifluoromethyl)benzidine residues. The content of the above-mentioned 2,3,6,7-naphthalenetetracarboxylic dianhydride residues relative to the total amount of the above-mentioned tetracarboxylic dianhydride residues is more than 5 mol% and less than 90 mol%. The content of the above-mentioned 2,2'-bis(trifluoromethyl)benzidine residues relative to the total amount of the above-mentioned diamine residues is more than 50 mol%.

[0015] [2] As described in [1] above, when the diamine residue contains a diamine residue that is different from the 2,2'-bis(trifluoromethyl)benzidine residue, the diamine residue that is different from the 2,2'-bis(trifluoromethyl)benzidine residue is a diamine residue that is derived from a diamine residue with a highest occupied orbital energy level of -5.20 eV or lower.

[0016] [3] As described in [2] above, the diamine residue that is different from the 2,2'-bis(trifluoromethyl)benzidine residue is selected from one or more residues in the group consisting of 4-aminobenzoic acid 4-aminophenyl ester residue, 9,9-bis(4-aminophenyl) benzoate residue, and 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether residue.

[0017] [4] The polyamide described in [2] or [3] above, wherein the content of diamine residues that are different from the above-mentioned 2,2'-bis(trifluoromethyl)benzidine residues is more than 1 mol% and less than 50 mol% relative to the total amount of the above-mentioned diamine residues.

[0018] [5] The polyamide described in [4] above, wherein the content of the above 3,3',4,4'-biphenyltetracarboxylic acid dianhydride residues is more than 30 mol% and less than 50 mol% relative to the total amount of the above tetracarboxylic acid dianhydride residues.

[0019] [6] The polyamide described in any of [1] to [5] above, wherein the difference between the average value of the lowest unoccupied orbital energy level of the tetracarboxylic dianhydride forming the above tetracarboxylic dianhydride residue and the average value of the highest occupied orbital energy level of the diamine forming the above diamine residue is 2.25 eV or more.

[0020] [7] A polyamide composition comprising the polyamide as described in any one of [1] to [6] above, and an organic solvent.

[0021] [8] The polyamide composition described above in [7] further contains a plasticizer.

[0022] [9] The polyamide composition described in [8] above, wherein the amount of the plasticizer is 0.001 parts by weight or more and 10 parts by weight or less relative to 100 parts by weight of the polyamide.

[0023]

[10] The polyamide composition as described in [8] or [9] above, wherein the plasticizer comprises phosphorus.

[0024]

[11] A polyimide, which is a polyimide of a polyamide as described in any of [1] to [6] above.

[0025]

[12] As described in

[11] above, the polyimide has a 1% weight reduction temperature of 500°C or higher.

[0026]

[13] A polyimide film comprising the polyimide as described above in

[11] or

[12] .

[0027]

[14] The polyimide film described above in

[13] has a transmittance of more than 40% for light with a wavelength of 400 nm.

[0028]

[15] The polyimide film described above in

[13] or

[14] has a haze of less than 1.0%.

[0029]

[16] A laminate having a support and a polyimide film as described in any one of

[13] to

[15] above.

[0030]

[17] A method for manufacturing a laminate, comprising a support and a polyimide film. By coating a support with the polyamide composition described in any one of [7] to

[10] above, a coating film containing the polyamide is formed, and the polyamide is amide-imidized by heating the coating film.

[0031]

[18] An electronic device having a polyimide film as described in any one of

[13] to

[15] above, and electronic components disposed on the polyimide film. [Effects of the Invention]

[0032] Polyimide manufactured using the polyamide of this invention exhibits excellent heat resistance and high transmittance of light at a wavelength of 400 nm. Therefore, polyimide manufactured using the polyamide of this invention is suitable as a material for electronic devices requiring heat resistance and transparency. Implementation

[0033] The preferred embodiments of the present invention will now be described in detail, but the present invention is not limited thereto.

[0034] First, the terms used in this specification will be explained. “Structural unit” refers to a repeating unit that constitutes a polymer. “Polyamide” is a polymer that contains the structural unit represented by the following general formula (1) (hereinafter sometimes referred to as “structural unit (1)”).

[0035] [Chemistry 1]

[0036] In general formula (1), A1 represents a tetracarboxylic dianhydride residue (derived from the tetravalent organic group of tetracarboxylic dianhydride), and A2 represents a diamine residue (derived from the divalent organic group of diamine).

[0037] The content of structural unit (1) relative to all structural units constituting polyamide is, for example, 50 mol% or more and 100 mol% or less, preferably 60 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less, further preferably 80 mol% or more and 100 mol% or less, further preferably 90 mol% or more and 100 mol% or less, or 100 mol%.

[0038] "1% weight reduction temperature" refers to the temperature at which the weight of polyimide at a measurement temperature of 150°C (based on a weight of 100% by weight) decreases by 1% compared to the aforementioned baseline. The method for determining the 1% weight reduction temperature is the same as that in the examples below or refers to the method in the examples below.

[0039] "Plasticizer" refers to a material that exists in liquid form during the amide imidization of at least a portion of polyamide.

[0040] Hereinafter, the term "system" will sometimes be added after the compound name to collectively refer to the compound and its derivatives. When "system" is added after the compound name to indicate the polymer name, it means that the repeating unit of the polymer is derived from the compound or its derivative. Also, tetracarboxylic dianhydride is sometimes referred to as "acid dianhydride". Furthermore, unless otherwise specified, the ingredients or functional groups exemplified in this specification may be used alone or in combination with two or more.

[0041] <Preferred Embodiment of the Invention> The polyamide in this embodiment (hereinafter, sometimes referred to as "polyamide (1)") has a tetracarboxylic acid dianhydride residue and a diamine residue.

[0042] In polyamide (1), the tetracarboxylic dianhydride residues include those selected from 3,3',4,4'-biphenyltetracarboxylic dianhydride residues, 9,9-bis(3,4-dicarboxyphenyl)furan dianhydride residues, 4,4'-oxophthalic anhydride residues, and spiro[11H-difurano[3,4-b:3',4'-i] -11,9'-[9H][11H][1,3,7,9-tetraketone residues, and 2,3,6,7-naphthalenetetracarboxylic acid dianhydride residues. That is, polyamide (1) comprises residues selected from 3,3',4,4'-biphenyltetracarboxylic acid dianhydride residues, 9,9-bis(3,4-dicarboxyphenyl)[11H][1,3,4-b:3',4'-i][1,3,4-b:3',4'-i][1,3,4-b:3',4'-i][1,3,4-b:3',4'-i][1,3,4'-b:3',4'-i][1,3,4'-b:3',4'-i][1,3' ...b:3',4'-i][1,3',4'-b:3',4'-b:3',4'-i][1,3',4'-b:3',4'-b:3',4'-i][1,3',4'-b:3',4'-b:3',4'-b:3',4'-b:3',4'-b:3',4'-b:3',4'-b:3',4'-b:3',4'-b:3',4'-b:3',3',4'-b:3',4'-b:3',4'-b: One or more residues from the group consisting of -11,9'-[9H][1,3,7,9-tetraketone residues, and 2,3,6,7-naphthalenetetracarboxylic dianhydride residues as tetracarboxylic dianhydride residues.

[0043] Furthermore, in polyacrylic acid (1), the diamine residue includes a 2,2'-bis(trifluoromethyl)benzidine residue. That is, polyacrylic acid (1) contains a 2,2'-bis(trifluoromethyl)benzidine residue as a diamine residue.

[0044] The 3,3',4,4'-biphenyltetracarboxylic acid dianhydride residues are derived from a portion of the structure of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (hereinafter, sometimes referred to as "BPDA"). The 9,9-bis(3,4-dicarboxyphenyl)furandianihydride residues are derived from a portion of the structure of 9,9-bis(3,4-dicarboxyphenyl)furandianihydride (hereinafter, sometimes referred to as "BPAF"). The 4,4'-oxophthalic anhydride residues are derived from a portion of the structure of 4,4'-oxophthalic anhydride (hereinafter, sometimes referred to as "ODPA"). Spiro[11H-difurano[3,4-b:3',4'-i] -11,9'-[9H][1,3,7,9-tetraone residues are derived from spiro[11H-difurano[3,4-b:3',4'-i][1,4-b][1,3,7,9-tetraone residues]. -11,9'-[9H][1,3,7,9-tetraone (hereinafter, sometimes referred to as "SFDA") has a partial structure. The 2,3,6,7-naphthalenetetracarboxylic acid dianhydride residue is derived from the partial structure of 2,3,6,7-naphthalenetetracarboxylic acid dianhydride (hereinafter, sometimes referred to as "NTCDA"). The 2,2'-bis(trifluoromethyl)benzidine residue is derived from the partial structure of 2,2'-bis(trifluoromethyl)benzidine (hereinafter, sometimes referred to as "TFMB"). Furthermore, the SFDA residue is a tetravalent organic group represented by the following chemical formula (2).

[0045] [Chemistry 2]

[0046] Furthermore, in polyacrylic acid (1), the content of NTCDA residues relative to the total amount of tetracarboxylic dianhydride residues is 5 mol% to 90 mol%. Moreover, in polyacrylic acid (1), the content of TFMB residues relative to the total amount of diamine residues is 50 mol% or more.

[0047] Generally, polyimides obtained from polyacrylic acids containing NTCDA and TFMB residues have a higher 1% weight reduction temperature (TD1) (excellent heat resistance) and a lower CTE due to their rigid structure. Furthermore, they can reduce internal stress (hereinafter sometimes simply referred to as "internal stress") generated during the formation of a polyimide film on a support to obtain a laminate. Compared to polyimides using pyromellitic dianhydride as the dianhydride monomer, polyimides using NTCDA as the dianhydride monomer tend to have a higher transmittance of light at a wavelength of 400 nm (hereinafter sometimes referred to as "400 nm transmittance"). However, the 400 nm transmittance of polyimides obtained from polyacrylic acids containing only NTCDA residues as tetracarboxylic dianhydride residues and only TFMB residues as diamine residues is insufficient for applications requiring high transparency.

[0048] The inventors conducted intensive research and found that polyimide obtained from polyamide (polyamide (1)) having one or more residues selected from the group consisting of BPDA residues, BPAF residues, ODPA residues and SFDA residues (hereinafter sometimes referred to as "specific acid dianhydride residues"), NTCDA residues, and TFMB residues, and with the content of NTCDA residues and TFMB residues in a specific range, exhibits excellent heat resistance and high 400 nm transmittance. Specifically, in polyamide (1), the content of NTCDA residues relative to the total amount of tetracarboxylic acid dianhydride residues is 5 mol% to 90 mol%, and the content of TFMB residues relative to the total amount of diamine residues is 50 mol% or more.

[0049] In order to obtain polyimide with excellent heat resistance by increasing the glass transition temperature (Tg), the content of NTCDA residues relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyimide (1) is preferably 10 mol% or more, more preferably 15 mol% or more, and even more preferably 20 mol% or more. Furthermore, in order to obtain polyimide capable of reducing internal stress, the content of NTCDA residues relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyimide (1) is preferably 85 mol% or less, more preferably 80 mol% or less.

[0050] In order to obtain polyimide with excellent heat resistance and higher 400 nm transmittance, the content of specific acid dianhydride residues relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyimide (1) is preferably 10 mol% to 95 mol%, more preferably 10 mol% to 90 mol%, and even more preferably 10 mol% to 80 mol%. Furthermore, when polyimide (1) has multiple types of specific acid dianhydride residues, the term "content of specific acid dianhydride residues" refers to the total content of multiple types of specific acid dianhydride residues.

[0051] To obtain polyimides with superior heat resistance, the dianhydride residue of the specific acid is preferably a BPDA residue. To obtain polyimides with superior transparency, the dianhydride residue of the specific acid is preferably one or more residues selected from the group consisting of BPAF residues, ODPA residues, and SFDA residues.

[0052] To obtain polyimide with higher transmittance at 400 nm, the specific acid dianhydride residue is preferably selected from one or more residues in the group consisting of BPAF residues and SFDA residues. Furthermore, to obtain polyimide with higher transmittance at 400 nm, the content of one or more residues in the group consisting of BPAF residues and SFDA residues (in the case where both BPAF residues and SFDA residues are present, the total content of such residues) relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyimide (1) is preferably 10 mol% to 50 mol%, more preferably 20 mol% to 50 mol%, and even more preferably 30 mol% to 50 mol%.

[0053] When polyamide (1) contains BPDA residues, in order to obtain polyimide with improved transparency and better heat resistance, the content of BPDA residues relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyamide (1) is preferably 5 mol% or more and 90 mol% or less, more preferably 5 mol% or more and 70 mol% or less, and even more preferably 5 mol% or more and 50 mol% or less.

[0054] When polyamide (1) contains BPAF residues, in order to obtain polyimide with improved heat resistance and better transparency, the content of BPAF residues relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyamide (1) is preferably 1 mol% or more and 50 mol% or less, more preferably 1 mol% or more and 40 mol% or less, and even more preferably 1 mol% or more and 30 mol% or less.

[0055] When polyamide (1) has ODPA residues, in order to obtain polyimide with improved heat resistance and better transparency, the content of ODPA residues relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyamide (1) is preferably 5 mol% or more and 30 mol% or less, more preferably 5 mol% or more and 20 mol% or less, and even more preferably 5 mol% or more and 10 mol% or less.

[0056] When polyamide (1) contains SFDA residues, in order to obtain polyimide with improved heat resistance and better transparency, the content of SFDA residues relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyamide (1) is preferably 1 mol% or more and 50 mol% or less, more preferably 1 mol% or more and 40 mol% or less, and even more preferably 1 mol% or more and 30 mol% or less.

[0057] In order to obtain polyimide with better heat resistance and higher 400 nm transmittance, the content of TFMB residues relative to the total amount of diamine residues constituting polyamide (1) is preferably 55 mol% or more, more preferably 60 mol% or more, even more preferably 65 mol% or more, even more preferably 70 mol% or more, or it can be 75 mol% or more, 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, or 100 mol.

[0058] When synthesizing polyacrylic acid (1), acid dianhydrides other than NTCDA and specific acid dianhydrides may be used as monomers without impairing their properties. Examples of acid dianhydrides other than NTCDA and specific acid dianhydrides include: pyromellitic dianhydride, p-phenyl bis(phenyl)trimethicone dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 4,4'-dioxophthalic anhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 2'-side-oxydispiro[bicyclo[2.2.1]heptane-2,1'-cyclopentane-3',2''-bicyclo[2.2.1]heptane]-5,6:5'',6''-tetracarboxylic acid dianhydride, and their derivatives. These can be used alone or in combination.

[0059] In order to obtain polyimide with better heat resistance and higher 400 nm transmittance, the total content of NTCDA residues and specific acid dianhydride residues relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyimide (1) is preferably 70 mol% or more, more preferably 75 mol% or more, more preferably 80 mol% or more, more preferably 85 mol% or more, and may also be 90 mol% or more, 95 mol% or more, or 100 mol.

[0060] In the synthesis of polyamide (1), diamines other than TFMB can be used as monomers without impairing their properties. Examples of diamines other than TFMB include: p-phenylenediamine, 4-aminobenzoic acid (hereinafter sometimes referred to as "BAAB"), 9,9-bis(4-aminophenyl)benzoate (hereinafter sometimes referred to as "BAFL"), 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (hereinafter sometimes referred to as "6FODA"), 1,4-cyclohexanediamine, 4,4'-diaminobenzonitrile, m-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenyl ether. Phenyl ether, N,N'-bis(4-aminophenyl)-terephthalamide, 4,4'-diaminodiphenylamine, meta-toluidine, o-toluidine, 4,4'-bis(4-aminophenoxy)biphenyl, 2-(4-aminophenyl)-6-aminobenzo[a]azole, 3,5-diaminobenzoic acid, 4,4'-diamino-3,3'-dihydroxybiphenyl, 4,4'-methylenebis(cyclohexylamine), 1,3-bis(3-aminopropyl)tetramethyldisiloxane and their derivatives may be used alone or in combination.

[0061] When polyamide (1) has a diamine residue (hereinafter, sometimes referred to as "any diamine residue") that is different from the TFMB residue, in order to obtain a polyimide with higher 400 nm transmittance, the arbitrary diamine residue is preferably a residue derived from a diamine with a highest occupied orbital energy level (hereinafter, sometimes referred to as "HOMO") of -5.20 eV or lower, more preferably a residue derived from a diamine with a HOMO of -5.30 eV or lower, further preferably a residue derived from a diamine with a HOMO of -5.40 eV or lower, and even more preferably a residue derived from a diamine with a HOMO of -5.50 eV or lower. Furthermore, when polyamide (1) has any diamine residue, in order to obtain a polyimide with higher 400 nm transmittance, polyamide (1) preferably has only residues derived from diamines with a HOMO of -5.20 eV or lower as arbitrary diamine residues. In order to improve the reactivity of the monomer during the synthesis of polyamide (1), the diamine residue is preferably derived from a diamine with a HOMO of -6.20 eV or higher.

[0062] Examples of residues derived from diamines with a HOMO of -5.20 eV or lower include BAAB residues, BAFL residues, and 6FODA residues. That is, when polyacrylic acid (1) has any diamine residue, in order to obtain a polyimide with higher 400 nm transmittance, the diamine residue is preferably selected from one or more residues in the group consisting of BAAB residues, BAFL residues, and 6FODA residues. Furthermore, when polyacrylic acid (1) has any diamine residue, in order to obtain a polyimide with higher 400 nm transmittance, polyacrylic acid (1) preferably has only one or more residues selected from the group consisting of BAAB residues, BAFL residues, and 6FODA residues as the diamine residue.

[0063] When polyamide (1) has any diamine residues, in order to obtain polyimide with excellent heat resistance and higher 400 nm transmittance, the content of any diamine residues (in the case of multiple types of any diamine residues, the total content) relative to the total amount of diamine residues constituting polyamide (1) is preferably 1 mol% or more and 50 mol% or less, more preferably 1 mol% or more and 40 mol% or less, further preferably 1 mol% or more and 30 mol% or less, further preferably 1 mol% or more and 20 mol% or less, or it can be 1 mol% or more and 15 mol% or 5 mol% or more and 15 mol% or less.

[0064] When polyamide (1) has any diamine residues and the content of any diamine residues (in the case of having multiple kinds of any diamine residues, the total content) is 1 mol% or more and 50 mol% or less relative to the total amount of diamine residues constituting polyamide (1), in order to obtain polyamide with better heat resistance, the content of BPDA residues is preferably 30 mol% or more and 50 mol% or less relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyamide (1).

[0065] To obtain polyimide with higher transmittance of 400 nm, the difference between the average value of the lowest unoccupied orbital energy level (LUMO) of the tetracarboxylic dianhydride residues forming polyamide (1) and the average value of the HOMO of the diamine residues forming polyamide (1) (hereinafter, sometimes referred to as "average energy level difference") is preferably 2.25 eV or higher, more preferably 2.30 eV or higher, and even more preferably 2.35 eV or higher, and may also be 2.40 eV or higher. Furthermore, the LUMO of the tetracarboxylic dianhydride and the HOMO of the diamine are both values ​​calculated by density functional theory (DFT). Also, the average energy level difference is calculated according to the formula "average energy level difference = average value of LUMO of tetracarboxylic dianhydride - average value of HOMO of diamine".

[0066] The "average LUMO of tetracarboxylic acid dianhydride" is the value obtained by multiplying the LUMO of NTCDA by the mole fraction of NTCDA, the value obtained by multiplying the LUMO of a specific acid dianhydride by the mole fraction of that specific acid dianhydride (when multiple specific acid dianhydrides are used, it is the value obtained by multiplying the LUMO of each specific acid dianhydride by the mole fraction of each specific acid dianhydride), and the value obtained by multiplying the LUMO of other acid dianhydrides used as needed by the mole fraction of other acid dianhydrides (when multiple other acid dianhydrides are used, it is the value obtained by multiplying the LUMO of each other acid dianhydride by the mole fraction of each other acid dianhydride). For example, in the case of Example 1 described below, 90 mol% of NTCDA (LUMO: -3.80 eV) and 10 mol% of BPAF (LUMO: -3.19 eV) as the specific acid dianhydride were used. Therefore, the average LUMO of the tetracarboxylic dianhydride used in Example 1 was (-3.80) × 0.9 + (-3.19) × 0.1 = -3.739 eV. The "average HOMO of the diamine" was also calculated using the same method as the "average LUMO of the tetracarboxylic dianhydride" described above.

[0067] In order to improve the reactivity of the monomer during the synthesis of polyamide (1), the above-mentioned average energy level difference is preferably 2.80 eV or less, more preferably 2.70 eV or less, and even more preferably 2.60 eV or less.

[0068] In order to obtain polyimide with better heat resistance and higher transmittance of light at a wavelength of 400 nm, polyamide (1) preferably satisfies the following condition 1, more preferably satisfies the following condition 2, and even more preferably satisfies the following condition 3. Condition 1: The content of NTCDA residues relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyacrylic acid (1) is more than 10 mol% and less than 90 mol%, and the content of TFMB residues relative to the total amount of diamine residues constituting polyacrylic acid (1) is more than 90 mol% and less than 100 mol%. Condition 2: The above condition 1 is satisfied, and the specific acid dianhydride residue is selected from one or more residues in the group composed of BPAF residues and SFDA residues. Condition 3: The above condition 2 is satisfied, and the content of one or more residues selected from the group consisting of BPAF residues and SFDA residues (in the case of having both BPAF residues and SFDA residues, the total content of them) is more than 10 mol% and less than 50 mol% relative to the total amount of tetracarboxylic acid dianhydride residues constituting polyacrylic acid (1).

[0069] Polyamide (1) can be synthesized by known general methods, such as reacting a diamine with a tetracarboxylic acid dianhydride in an organic solvent. An example of a specific synthesis method for polyamide (1) will be described. First, a diamine solution is prepared by dissolving or dispersing the diamine in an organic solvent in an inert gas atmosphere such as argon or nitrogen. Then, the tetracarboxylic acid dianhydride, either dissolved or dispersed in an organic solvent, or in a solid state, is added to the diamine solution.

[0070] When polyamides are synthesized using diamines and tetracarboxylic dianhydrides, the desired polyamide (a polymer of diamines and tetracarboxylic dianhydrides) can be obtained by adjusting the mass of the diamine (the mass of each diamine when multiple diamines are used) and the mass of the tetracarboxylic dianhydride (the mass of each tetracarboxylic dianhydride when multiple tetracarboxylic dianhydrides are used). The molar fraction of each residue in polyamide (1) is, for example, consistent with the molar fraction of each monomer (diamine and tetracarboxylic dianhydride) used in the synthesis of polyamide (1). Furthermore, by blending two polyamides, polyamide (1) containing multiple tetracarboxylic dianhydride residues and multiple diamine residues can also be obtained. The temperature conditions for the reaction of diamines and tetracarboxylic dianhydrides, i.e., the synthesis reaction of polyamide (1), are not particularly limited, for example, in the range of 20°C to 150°C. The reaction time for the synthesis of polyamide (1) is, for example, between 10 minutes and 30 hours.

[0071] The organic solvent used in the synthesis of polyacrylic acid (1) is preferably a solvent capable of dissolving the tetracarboxylic acid dianhydride and diamine used, and more preferably a solvent capable of dissolving the polyacrylic acid (1) to be generated. Examples of organic solvents used in the synthesis of polyacrylic acid (1) include: urea solvents such as tetramethylurea and N,N-dimethylethylurea; urethane solvents such as dimethyl urethane; urethane solvents such as diphenyl urethane and tetramethyl urethane; N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), and 3-methoxy-N,N - Amine solvents such as dimethylpropionic acid (MPA) and hexamethylphosphonic triamine; ester solvents such as γ-butyrolactone; halogenated alkyl solvents such as chloroform and dichloromethane; aromatic hydrocarbon solvents such as benzene and toluene; phenol solvents such as phenol and cresol; ketone solvents such as cyclopentanone; ether solvents such as tetrahydrofuran, 1,3-dioxolane, 1,4-dimethyl ether, dimethyl ether, diethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, and p-cresol methyl ether. These solvents are usually used alone, but two or more can be combined as needed. To improve the solubility and reactivity of polyamide (1), the organic solvent used in the synthesis reaction of polyamide (1) is preferably one or more solvents selected from the group consisting of amide solvents, ketone solvents, ester solvents and ether solvents, and more preferably amide solvents (more specifically, DMF, DMAC, NMP, MPA, etc.). Furthermore, the synthesis reaction of polyamide (1) is preferably carried out under an inert gas atmosphere such as argon or nitrogen.

[0072] The weight-average molecular weight of polyacrylic acid (1) is preferably in the range of 10,000 to 1,000,000, more preferably in the range of 20,000 to 500,000, and even more preferably in the range of 30,000 to 200,000, depending on its application. If the weight-average molecular weight is 10,000 or more, it is easy to form a coated film or polyimide film (membrane) from polyacrylic acid (1) or polyimide obtained using polyacrylic acid (1). On the other hand, if the weight-average molecular weight is 1,000,000 or less, it exhibits sufficient solubility with respect to solvents, and therefore a coated film or polyimide film with a smooth surface and uniform thickness can be obtained using the following polyacrylic acid composition. The weight-average molecular weight used here refers to the polyethylene oxide equivalent value measured using gel permeation chromatography (GPC).

[0073] Furthermore, as a method for controlling the molecular weight of polyamide (1), examples include using an excess of either the dianhydride or the diamine, or quenching the reaction by reacting with a monofunctional anhydride or amine such as phthalic anhydride or aniline. When polymerization is carried out in excess of either the dianhydride or the diamine, a feed molar ratio between 0.95 and 1.05 can yield a polyamide film with sufficient strength. Moreover, the aforementioned feed molar ratio is the ratio of the total mass of the diamines used in the synthesis of polyamide (1) to the total mass of the dianhydride used in the synthesis of polyamide (1) (total mass of diamines / total mass of dianhydride). Furthermore, by using phthalic anhydride, maleic anhydride, aniline, etc. for end capping, the coloring of polyimide obtained by using polyamide (1) can be further reduced.

[0074] The polyamide composition of this embodiment contains polyamide (1) and an organic solvent. Examples of organic solvents included in the polyamide composition of this embodiment include those capable of being used in the synthesis reaction of the polyamide (1). Preferably, it is a solvent selected from the group consisting of amide-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents, and more preferably, an amide-based solvent (more specifically, DMF, DMAC, NMP, MPA, etc.). When polyamide (1) is obtained by the above method, the reaction solution (the solution after the reaction) itself can also be used as the polyamide composition of this embodiment. Alternatively, the solid polyamide (1) obtained by removing the solvent from the reaction solution can be dissolved in an organic solvent to prepare the polyamide composition of this embodiment. Furthermore, there is no particular limitation on the content of polyamide (1) in the polyamide composition of this embodiment, for example, it is more than 1% by weight and less than 80% by weight relative to the total amount of polyamide composition.

[0075] Furthermore, in order to shorten the heating time and improve the performance characteristics, the polyamide composition of this embodiment may also contain a amide imidization accelerator and / or a dehydration catalyst.

[0076] There are no particular limitations on the aceiminization accelerators mentioned above, and tertiary amines can be used. Heterocyclic tertiary amines are preferred. Preferred examples of heterocyclic tertiary amines include pyridine, methylpyridine, quinoline, isoquinoline, and imidazoles. Preferred examples of dehydration catalysts include acetic anhydride, propionic anhydride, butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride.

[0077] From the viewpoints of shortening heating time and performance characteristics, the amount of amide accelerator relative to 100 parts by weight of polyamide (1) is preferably 0.1 parts by weight to 10 parts by weight, and more preferably 0.5 parts by weight to 5 parts by weight. Furthermore, from the viewpoints of shortening heating time and performance characteristics, the amount of dehydration catalyst relative to 100 parts by weight of polyamide (1) is preferably 0.1 parts by weight to 10 parts by weight, and more preferably 0.5 parts by weight to 5 parts by weight.

[0078] As an amide imidization accelerator, imidazoles are preferred. Furthermore, in this specification, imidazoles refer to compounds having a 1,3-diazole ring (1,3-diazole ring structure). There are no particular limitations on the imidazoles that can be added to the polyamide composition of this embodiment; examples include: 1H-imidazolium, 2-methylimidazolium, 2-undecylimidazolium, 2-heptadecylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 1-benzyl-2-phenylimidazolium, etc. Among these, 1,2-dimethylimidazolium, 1-benzyl-2-methylimidazolium, and 1-benzyl-2-phenylimidazolium are preferred, and more preferably 1,2-dimethylimidazolium and 1-benzyl-2-methylimidazolium.

[0079] The content of imidazoles relative to 1 mol of amide groups in polyamide (1) is preferably 0.005 mol to 0.1 mol, more preferably 0.01 mol to 0.08 mol, and even more preferably 0.015 mol to 0.050 mol. By containing 0.005 mol or more of imidazoles, the film strength and transparency of polyimide can be improved. By keeping the content of imidazoles at 0.1 mol or less, the storage stability of polyamide (1) can be maintained and the heat resistance can be improved. Furthermore, in this specification, "amide groups in polyamide (1)" refers to amide groups generated by the polymerization reaction of diamine and tetracarboxylic dianhydride.

[0080] There are no particular limitations on the method of mixing polyacrylic acid (1) and imidazoles. From the viewpoint of ease of controlling the molecular weight of polyacrylic acid (1), it is preferable to add imidazoles to the polymerized polyacrylic acid (1). At this time, imidazoles can be added directly to polyacrylic acid (1), or the imidazoles can be dissolved in a solvent beforehand and the solution can be added to polyacrylic acid (1). There are no particular limitations on the method of addition. Imidazoles can also be added to a solution containing polymerized polyacrylic acid (1) (the solution after reaction) to prepare the polyacrylic acid composition of this embodiment.

[0081] In the polyamide composition of this embodiment, various organic or inorganic low-molecular-weight compounds or high-molecular-weight compounds can also be formulated as additives. Examples of additives include plasticizers, antioxidants, dyes, surfactants, leveling agents, silicones, microparticles, and sensitizers. Microparticles include organic microparticles containing polystyrene, polytetrafluoroethylene, etc., or inorganic microparticles containing colloidal silica, carbon, layered silicates, etc., which can also have porous or hollow structures. Furthermore, the function and morphology of the microparticles are not particularly limited; for example, they can be pigments, fillers, or fibrous particles.

[0082] The effects of the aforementioned plasticizer, which can be incorporated into the polyimide composition of this embodiment, will be explained. Generally, when a transparent polyimide film is desired, theoretically, it is sufficient to design polyimides with large band gaps of HOMO and LUMO. Therefore, TFMB with low electron-donating activity is more effective in obtaining a transparent polyimide film. On the other hand, since TFMB with low electron-donating activity has lower nucleophilicity, a slower reaction rate and a slower amide formation rate can be predicted. The inventors have studied the amide formation rate and obtained the following insights. That is, the amide ratios of general colored polyimides obtained from BPDA and p-phenylenediamine and transparent polyimides obtained from PMDA or BPDA and TFMB were compared. The results showed that colored polyimides achieved amide ratios of over 90% at an amide reaction temperature of 300°C and close to 100% at an amide reaction temperature of 350°C. However, transparent polyimides achieved only about 75% amide ratios at an amide reaction temperature of 300°C and only about 80% at an amide reaction temperature of 350°C, showing a significant difference in amide ratio.

[0083] Generally, the driving force for the dehydration and ring closure of polyacrylic acid to form polyimide via thermal acetilimation is significantly influenced by molecular movement caused by heat and plasticizing effect caused by solvent. Ideally, complete acetilimation should be performed above the glass transition temperature of the polyimide. However, in combinations of rigid acid dianhydrides such as NTCDA and TFMB, the resulting polyimide may have a glass transition temperature exceeding 400°C, which is higher than the heat treatment temperature for film formation. Therefore, in the acetilimation reaction of rigid acid dianhydrides such as NTCDA and TFMB, there is a possibility that acetilimation may not be complete. Therefore, in high-temperature processes such as those using polyimide films (e.g., dehydrogenation treatment of TFT elements), there is a possibility that unreacted sites in the polyimide film may undergo amide formation, generating low molecular weight components from the polyimide film and producing gas release (e.g., hydrogen fluoride), thereby causing barrier film peeling or TFT corrosion. In contrast, by adding a plasticizer to the polyamide composition, sufficient molecular movement is provided during the amide formation of polyamide (1), not only is amide formation complete, but the depolymerization of polyamide (1) is also suppressed, thereby suppressing the generation of gas release (especially hydrogen fluoride). Furthermore, by adding plasticizers to the polyamide composition, the polyamide (1) is given molecular movement, thereby making it easier to remove solvents. The amount of residual solvent in the membrane (polyimide membrane) is reduced, and the coloring of the membrane is also reduced.

[0084] As a plasticizer that can be used in this embodiment, it is preferably a material dissolved in the solvent used during the amide formation of polyacrylic acid (1). Furthermore, in order to impart sufficient molecular mobility to polyacrylic acid (1) during amide formation, the plasticizer is preferably non-volatile at low temperatures. Therefore, the boiling point of the plasticizer is preferably 50°C or higher, more preferably 100°C or higher, and even more preferably 150°C or higher. Furthermore, in order to impart sufficient molecular mobility to polyacrylic acid (1) during amide formation, the plasticizer preferably does not have a decomposition temperature below its boiling point.

[0085] Regarding the amount of plasticizer, from the viewpoint of avoiding the decomposition of the plasticizer itself, it is preferably 10 parts by weight or less relative to 100 parts by weight of polyacrylic acid (1). Furthermore, regarding the amount of plasticizer, from the viewpoint of imparting sufficient molecular mobility to polyacrylic acid (1) and avoiding the decomposition of the plasticizer itself, it is preferably 0.001 parts by weight or more and 10 parts by weight relative to 100 parts by weight of polyacrylic acid (1), more preferably 0.01 parts by weight or more and 10 parts by weight, further preferably 0.01 parts by weight or more and 8 parts by weight, and further preferably 0.1 parts by weight or more and 6 parts by weight.

[0086] To further suppress the generation of hydrogen fluoride during use in high-temperature processes, the plasticizer is preferably selected from one or more of the group consisting of phosphorus-containing compounds, polyalkylene glycols, and aliphatic diesters.

[0087] Examples of phosphorus-containing compounds include those represented by the general formulas (3-1) to (3-10) below. In the general formulas (3-1) to (3-10) below, R5, R6 and R7 independently represent hydrogen atoms, monovalent organic groups or polyvalent organic groups, respectively, R8 represents polyvalent organic groups, and n represents the degree of polymerization.

[0088] [Chemistry 3]

[0089] Preferred examples of phosphorus-containing compounds include: phosphoric acid compounds, phosphite compounds, phosphonic acid compounds, hypophosphonic acid compounds, phosphine compounds, phosphine oxide compounds, phosphine compounds, and phosphazene compounds. Phosphorus-containing compounds can also be esters or condensates of the compounds listed above, can contain cyclic structures, and can form salts with amines, etc. Furthermore, among these phosphorus-containing compounds, there are also those that are tautomerically related, such as phosphite compounds and phosphonic acid compounds, and can exist in any state.

[0090] Specific examples of phosphoric acid compounds include: trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, tri(xylene) phosphate, tri(isopropylphenyl) phosphate, trinaphthalene phosphate, cresoldiphenyl phosphate, xylenediphenyl phosphate, diphenyl(2-ethylhexyl) phosphate, di(isopropylphenyl) phosphate, monoisodecyl phosphate, acid 2-propenyloxyethyl phosphate, acid 2-methpropenyloxyethyl phosphate, diphenyl-2-propenyloxyethyl phosphate, diphenyl-2-methpropenyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, bisphenol A bis(diphenyl phosphate), tri(β-chloropropyl) phosphate, etc.

[0091] Specific examples of phosphite compounds include: triphenyl phosphite, tri(nonylphenyl) phosphite, tricresol phosphite, triethyl phosphite, triisobutyl phosphite, tri(2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tri(tetrazyl) phosphite, diphenyl phosphite, diethyl phosphite, dibutyl phosphite, dimethyl phosphite, diphenyl phosphite mono(2-ethylhexyl) ester, diphenyl phosphite monodecyl ester, diphenyl phosphite mono(tetrazyl) ester, trilauryl trithiophosphite, and diethyl hydrogen phosphite. Bis(2-ethylhexyl) hydrogen phosphite, dilaurate hydrogen phosphite, dioleyl hydrogen phosphite, diphenyl hydrogen phosphite, tetraphenyldipropylene glycol diphosphite, bis(decyl)pentaerythritol diphosphite, bis(tetrazyl)pentaerythritol diphosphite, tristearate phosphite, distearate pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite, triisodecyl phosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosspiro[5.5]undecane, etc.

[0092] Examples of the aforementioned condensates include condensed phosphate esters. Specific examples of condensed phosphate esters include: trialkyl polyphosphate, resorcinol polyphenyl phosphate, resorcinol poly(di-2,6-xylyl) phosphate, and hydroquinone poly(2,6-xylyl) phosphate. Commercially available condensed phosphate esters include, for example, "CR-733S" manufactured by Daihachi Chemical Industry Co., Ltd., "CR-741" manufactured by Daihachi Chemical Industry Co., Ltd., "PX-200" manufactured by Daihachi Chemical Industry Co., Ltd., and "FP-600" manufactured by ADEKA Co., Ltd.

[0093] Specific examples of phosphazene compounds include: phenoxycyclophosphonitrile ("FP-110" manufactured by Fushimi Pharmaceutical Co., Ltd.) and cyclic cyanophenoxyphosphonitrile ("FP-300" manufactured by Fushimi Pharmaceutical Co., Ltd.).

[0094] Specific examples of polyalkyl glycols include polypropylene glycol and polyethylene glycol.

[0095] Specific examples of aliphatic diesters include: dibutyl adipate, diisobutyl adipate, bis(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, bis[2-(2-butoxyethoxy)ethyl] adipate, bis(2-ethylhexyl) azelaate, dibutyl sebacate, bis(2-ethylhexyl) sebacate, diethyl succinate, etc.

[0096] Furthermore, plasticizers, as long as they can exert a plasticizing effect, can be low-molecular-weight organic compounds or thermoplastic resins. Examples of such low-molecular-weight organic compounds include organic compounds with a molecular weight of approximately 1,000 or less, such as: phenolic compounds; phthalimide compounds such as phthalimide, N-phenylphthalimide, N-glycidylphthalimide, N-hydroxyphthalimide, and cyclohexylthiophthalimide; and maleic anhydride compounds such as N,N-p-phenylbis(cis-butene)diimide and 2,2'-(ethylenedioxy)bis(ethylcis-butene)diimide. Examples of such thermoplastic resins include polyimides or polyamines with asymmetric structures.

[0097] Furthermore, in order to exhibit appropriate adhesion to the support, the polyamide composition of this embodiment can contain a silane coupling agent. There are no particular restrictions on the type of silane coupling agent that can be used, but from the viewpoint of reactivity with polyamide (1), compounds containing amine groups are particularly preferred.

[0098] The mixing ratio of the silane coupling agent to 100 parts by weight of polyamide (1) is preferably 0.01 parts by weight or more and 0.50 parts by weight, more preferably 0.01 parts by weight or more and 0.10 parts by weight, and even more preferably 0.01 parts by weight or more and 0.05 parts by weight. By making the mixing ratio of the silane coupling agent 0.01 parts by weight or more, the peeling inhibition effect on the support can be fully exerted. By making the mixing ratio of the silane coupling agent 0.50 parts by weight or less, the decrease in molecular weight of polyamide (1) can be inhibited, thereby inhibiting the embrittlement of the polyimide film.

[0099] The polyimide of this embodiment is a amide of the aforementioned polyamide (1). The polyimide of this embodiment can be obtained by known methods, and its manufacturing method is not particularly limited. Hereinafter, an example of a method for obtaining the polyimide of this embodiment by amide-imidizing polyamide (1) will be described. Amididization is carried out by dehydrating and ring-closing polyamide (1). This dehydration and ring-closing can be carried out by an azeotropic method using an azeotropic solvent, a thermal method, or a chemical method. Furthermore, the amide-imidization from polyamide (1) to polyimide can be any ratio of 1% to 100%. That is, a portion of the amide-imidized polyamide (1) can also be synthesized. Especially when amide formation is carried out by heating, the ring-closing reaction from polyacrylic acid (1) to polyimide and the hydrolysis of polyacrylic acid (1) may occur simultaneously, resulting in a lower molecular weight of polyimide than that of polyacrylic acid (1). Therefore, from the viewpoint of improving mechanical properties, it is preferable to amide form a portion of the polyacrylic acid (1) in the polyacrylic acid composition before forming the polyimide film described below. In this specification, the polyacrylic acid that has been amide formed is sometimes referred to as "polyacrylic acid".

[0100] The dehydration and ring-closure of polyamide (1) can be achieved simply by heating polyamide (1). The method of heating polyamide (1) is not particularly limited; for example, after coating the polyamide composition of this embodiment onto a support such as a glass substrate, metal plate, or PET film (polyethylene terephthalate film), heat treatment of polyamide (1) can be performed at a temperature between 40°C and 500°C. According to this method, a laminate of this embodiment is obtained having a support and a polyimide film disposed on the support (specifically, a polyimide film containing a polyimide derivative of polyamide (1)). Alternatively, the polyamide composition can be placed directly into a container coated with a fluoropolymer release agent and heated and dried under reduced pressure to achieve dehydration and ring-closure of the polyamide (1). Polyimide can be obtained by performing dehydration and ring-closure of polyamide (1) using these methods. Furthermore, the heating time for each of the above treatments varies depending on the amount of polyamide composition being treated or the heating temperature, but generally, it is preferred to be set in the range of 1 minute to 300 minutes after the treatment temperature reaches the maximum temperature.

[0101] The polyimide film of this embodiment (more specifically, a polyimide film containing a polyimide compound of polyacrylic acid (1)) is colorless, transparent, and has low yellowness, and possesses the ability to withstand the glass transfer temperature (heat resistance) of the TFT fabrication process, thus making it suitable as a transparent substrate material for flexible displays. Regarding the content of polyimide (more specifically, a polyimide compound of polyacrylic acid (1)) in the polyimide film of this embodiment, relative to the total amount of the polyimide film, it is, for example, 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, and may also be 100% by weight. Examples of components in the polyimide film other than polyimide include the aforementioned additives (more specifically, microparticles, etc.).

[0102] The electronic device (more specifically, a flexible device, etc.) of this embodiment has the polyimide film of this embodiment and electronic components disposed directly or indirectly on the polyimide film. When manufacturing the electronic device of this embodiment for use in a flexible display, firstly, an inorganic substrate such as glass is used as a support, and a polyimide film is formed thereon. Then, electronic components such as TFTs are disposed (formed) on the polyimide film, thereby forming the electronic device on the support. The TFT formation step is usually carried out in a wide temperature range of 150°C to 650°C, but in order to substantially achieve the desired performance, an oxide semiconductor layer or an a-Si (amorphous silicon) layer is formed at 300°C or higher, and sometimes a-Si is further crystallized using lasers or the like.

[0103] At this point, when the thermal decomposition temperature of the polyimide film is low, gas release may occur during the formation of electronic components. This gas release may adhere to the oven as sublimation, causing oven contamination, or cause peeling of inorganic films (such as the barrier films described below) or electronic components formed on the polyimide film. Therefore, the 1% weight loss temperature of polyimide is preferably 500°C or higher. The higher the upper limit of the 1% weight loss temperature of polyimide, the better, for example, 600°C. The 1% weight loss temperature can be adjusted, for example, by changing the content of residues with rigid structures (more specifically, NTCDA residues, BPDA residues, etc.). To explain in more detail, before forming the TFT, an inorganic film such as a silicon oxide film (SiOx film) or a silicon nitride film (SiNx film) is formed on the polyimide film as a barrier film. At this point, if the heat resistance of polyimide is low, if amide oxidation is incomplete, or if there is a large amount of residual solvent, polyimide may peel off from the inorganic film during high-temperature processes following the deposition of the inorganic film due to volatile components such as decomposition gases. Therefore, ideally, in addition to the 1% weight loss temperature of polyimide being above 500°C, the weight loss rate when isothermally holding polyimide within the temperature range of 400°C to 450°C should not reach 1%.

[0104] Furthermore, when the glass transition temperature (Tg) of polyimide is significantly lower than the process temperature, positional shifts may occur during the formation of electronic components. Therefore, the Tg of polyimide is preferably 300°C or higher, more preferably 350°C or higher, further preferably 400°C or higher, and even more preferably 420°C or higher. A higher upper limit for the Tg of polyimide is preferable, for example, 500°C. Also, generally speaking, the coefficient of thermal expansion of the glass substrate is less than that of the resin, thus internal stress will be generated between the glass substrate and the polyimide film. If the internal stress of the glass substrate used as a support or the polyimide film laminate containing the electronic components is high, the laminate containing the polyimide film will expand during the high-temperature TFT formation step and then shrink when cooled to room temperature, resulting in problems such as warping or breakage of the glass substrate and peeling of the polyimide film from the glass substrate. Therefore, the internal stress between the polyimide film and the glass substrate is preferably below 40 MPa, more preferably below 35 MPa, further preferably below 30 MPa, and even more preferably below 25 MPa. The method for measuring the internal stress is the same as or based on the method described in the examples below.

[0105] If bulges exist at the interface between the polyimide film and the support (e.g., a glass substrate), there is a risk of polyimide film peeling off during the formation of electronic components, or a decrease in yield when peeling off the polyimide film after the formation of electronic components. Furthermore, "bulges" refer to a state where poor adhesion occurs between the polyimide film and other material layers (more specifically, the glass substrate, barrier film, etc.) due to byproducts generated during amide formation or residual solvents. Specific examples of "bulges" include: polyimide film bulging from the glass substrate; partial damage to the polyimide film resulting in interlayer delamination between the polyimide film and other material layers; and barrier film bulging from the polyimide film. Generally, polyimide films obtained from polyacrylic acids containing BPDA and BAAB residues have poor air permeability due to their tightly packed molecular chains, making them prone to bulging at the interface with the support (e.g., a glass substrate). According to the inventors' research, it has been determined that introducing a loose or flexible structure into or at the ends of the polyacrylic acid molecular chains can prevent bulging. In particular, polyacrylic acids containing BPAF or SFDA residues, due to their loose structure, can combine good air permeability with a high glass transition temperature.

[0106] The polyimide of this embodiment is suitable as a material for display substrates such as TFT substrates or touch panel substrates. When using polyimide for the above-mentioned applications, in most cases, the method described above is used to form electronic devices on a support (more specifically, electronic devices obtained by forming electronic components on a polyimide film), and then peeling the polyimide film off the support. Furthermore, alkali-free glass is suitable as the material for the support. Hereinafter, an example of a method for manufacturing a laminate of polyimide film and support will be described in detail.

[0107] First, the polyamide composition of this embodiment is coated (cast) onto a support to form a laminate containing a coating film containing polyamide (1) and a support containing the coating film. Next, the laminate containing the coating film is heated at a temperature of, for example, 40°C to 200°C. The heating time is, for example, 3 minutes to 120 minutes. Alternatively, a multi-stage heating process can be provided, such as heating the laminate containing the coating film at 50°C for 30 minutes, and then heating it at 100°C for 30 minutes. Next, in order to promote the amide imidization of the polyamide (1) in the coating film, the laminate containing the coating film is heated at a maximum temperature of, for example, 200°C to 500°C. The heating time (heating time at the maximum temperature) is, for example, 1 minute to 300 minutes. Preferably, the temperature is gradually increased from a low temperature to the maximum temperature. The heating rate is preferably 2°C / min to 10°C / min, more preferably 4°C / min to 10°C / min. Furthermore, the maximum temperature is preferably in the range of 250°C to 450°C. If the maximum temperature is above 250°C, amide maturation is fully carried out; if the maximum temperature is below 450°C, thermal degradation or discoloration of the polyamide can be suppressed. Also, it can be maintained at any temperature for any time before reaching the maximum temperature. The amide maturation reaction can be carried out in air, under reduced pressure, or in an inert gas such as nitrogen. To exhibit higher transparency, it is preferable to carry out the reaction under reduced pressure or in an inert gas such as nitrogen. Furthermore, known devices such as hot air ovens, infrared ovens, vacuum ovens, non-oxidizing ovens, and heating plates can be used as heating devices. After these steps, the polyamide (1) in the coating film is amide-iminated, and a laminate of the support and the polyamide film (a film containing the amide of polyamide (1)) can be obtained (i.e., the laminate of this embodiment).

[0108] The method for peeling the polyimide film from the obtained support and the polyimide film stack can be any known method. For example, it can be peeled by hand, or by mechanical devices such as drive rollers or robots. Alternatively, a method can be used to provide a release layer between the support and the polyimide film; or a method can be used to peel the polyimide film by forming a silicon oxide film on a support with multiple grooves, using the silicon oxide film as a substrate layer to form the polyimide film, and then allowing the silicon oxide etching solution to wet between the support and the silicon oxide film. Furthermore, a method can also be used to separate the polyimide film by irradiating it with laser light.

[0109] The transparency of polyimide films can be evaluated using total light transmittance (TT) according to JIS K7361-1:1997 and haze according to JIS K7136-2000. When polyimide films are used for applications requiring high transparency, the total light transmittance of the polyimide film is preferably 75% or more, more preferably 80% or more. Furthermore, when polyimide films are used for applications requiring high transparency, the haze of the polyimide film is preferably 1.5% or less, more preferably 1.2% or less, and even more preferably 1.0% or less, or 0%. Haze can be adjusted by, for example, changing the content of TFMB residues in polyamide (1). In applications requiring high transparency, polyimide films are required to have high transmittance across the entire wavelength range. However, polyimide films tend to absorb light at shorter wavelengths, often resulting in a yellowish tint. To utilize polyimide films for applications requiring high transparency, it is preferable to minimize the coloring of the polyimide film. Specifically, for applications requiring high transparency, the yellowness index (YI) of the polyimide film is preferably below 25, more preferably below 20, and can also be 0. YI can be measured according to JIS K7373-2006. Thus, polyimide films with reduced coloring and thus improved transparency are suitable for transparent substrates used as glass replacements, or for substrates with sensors or camera modules mounted on the back.

[0110] Furthermore, as mentioned above, in applications requiring transparency, from the perspective of color reproduction, a higher transmittance of blue light (light with a wavelength around 470 nm) is particularly desirable, and practically, a higher transmittance of light with a wavelength of 400 nm (400 nm transmittance) is required. From the perspective of color reproduction, the 400 nm transmittance of polyimide films is preferably 40% or higher, and more preferably 45% or higher. There is no particular upper limit to the 400 nm transmittance of polyimide films, and it can also be 100%.

[0111] Furthermore, in the light extraction methods of flexible displays, there are two types: top-emitting method, which extracts light from the front side of the TFT, and bottom-emitting method, which extracts light from the back side of the TFT. The top-emitting method is characterized by its ability to easily increase the aperture ratio because the light is not blocked by the TFT, resulting in high-resolution image quality. The bottom-emitting method is characterized by its ease of manufacturing, as it facilitates the alignment of the TFT and pixel electrodes. If the TFT is transparent, the aperture ratio can also be increased in the bottom-emitting method; therefore, large displays tend to adopt the easier-to-manufacture bottom-emitting method. The polyimide film of this embodiment has a low YI and excellent heat resistance, thus it can be applied to either of the aforementioned light extraction methods.

[0112] Furthermore, in batch manufacturing processes where a polyamide composition is coated onto a support such as a glass substrate, and then heated to imidize it to form electronic components, followed by the peeling off of the polyimide film, it is preferable to have excellent adhesion between the support and the polyimide film. Here, adhesion refers to adhesion strength. In the manufacturing process where electronic components are formed on the polyimide film on the support, and the polyimide film with the formed electronic components is peeled off from the support, excellent adhesion between the polyimide film and the support allows for more accurate formation or mounting of the electronic components. From the viewpoint of improving productivity, in the manufacturing process of placing electronic components on a support with a polyimide film as a separator, the higher the peel strength between the support and the polyimide film, the better. Specifically, the peel strength is preferably 0.05 N / cm or higher, and more preferably 0.1 N / cm or higher.

[0113] In the manufacturing process described above, the polyimide film self-supporting body is typically peeled from the polyimide film laminate using laser irradiation. In this case, the polyimide film must absorb the laser light; therefore, the cutoff wavelength of the polyimide film must be longer than the wavelength of the laser light used for peeling. Laser peeling often uses XeCl excimer lasers with a wavelength of 308 nm; therefore, the cutoff wavelength of the polyimide film is preferably 312 nm or higher, and more preferably 330 nm or higher. On the other hand, if the cutoff wavelength is too long, the polyimide film will tend to turn yellow; therefore, the cutoff wavelength of the polyimide film is preferably 390 nm or lower. From the perspective of balancing transparency (low yellowing level) and processability via laser peeling, the cutoff wavelength of the polyimide film is preferably between 320 nm and 390 nm, and more preferably between 330 nm and 380 nm. Furthermore, the cutoff wavelength in this specification refers to the wavelength at which the transmittance, as measured by a UV-Vis spectrophotometer, becomes 0.1% or less.

[0114] The polyamide composition and polyimide of this embodiment can be directly used in coating or molding processes for manufacturing articles or components, but can also be used as materials for further coating or other treatments on molded articles formed into films. For use in coating or molding processes, the polyamide composition or polyimide can be dissolved or dispersed in an organic solvent as needed, and then, as needed, photocurable components, thermocurable components, non-polymerizable adhesive resins and other components can be formulated to prepare a composition containing polyamide (1) or polyimide.

[0115] Various inorganic films, such as metal oxide films or transparent electrodes, can also be formed on the surface of the polyimide film in this embodiment. There are no particular limitations on the method for forming these inorganic films; examples include sputtering, vacuum evaporation, ion plating, and other PVD (Physical Vapor Deposition) methods, or CVD (Chemical Vapor Deposition) methods.

[0116] In addition to its heat resistance, low thermal expansion, and transparency, the polyimide film of this embodiment exhibits low internal stress when formed into a laminate with a glass substrate. Furthermore, it ensures excellent adhesion to inorganic materials during high-temperature processes. Therefore, it is preferably used in fields and products where these properties can be utilized. For example, the polyimide film of this embodiment is preferably used in image display devices such as liquid crystal displays, organic EL displays, and electronic paper, printed materials, color filters, flexible displays, optical films, 3D displays, touch panels, transparent conductive film substrates, and solar cells. More preferably, it is used as a replacement material for currently used glass components. In these applications, the thickness of the polyimide film is, for example, 1 μm to 200 μm, preferably 5 μm to 100 μm. The thickness of the polyimide film can be measured using a laser hologram.

[0117] Furthermore, the polyamide composition of this embodiment is suitable for batch device manufacturing processes in which the polyamide composition is coated onto a support, heated to induce amide imidization, and electronic components are formed, followed by the peeling off of the polyamide film. Therefore, this embodiment also includes a method for manufacturing an electronic device, which includes the steps of coating a polyamide composition onto a support, heating to induce amide imidization, and forming electronic components on the polyamide film formed on the support. Furthermore, this method for manufacturing an electronic device may also include the step of peeling the polyamide film on which the electronic components are formed from the support. [Example]

[0118] The following describes embodiments of the present invention, but the scope of the present invention is not limited to the following embodiments.

[0119] <Methods for Determining Physical Properties> First, the method for determining the physical properties of polyimide (polyimide film) will be explained.

[0120] [400 nm transmittance] For the polyimide films in each laminate obtained in the following examples and comparative examples, the transmittance of light at a wavelength of 400 nm was measured using a UV-Vis-NIR spectrophotometer (V-650 manufactured by Nippon Spectrophotometer Co., Ltd.). When the transmittance at 400 nm was 40% or higher, it was evaluated as "high transmittance of light at a wavelength of 400 nm". On the other hand, when the transmittance at 400 nm was less than 40%, it was evaluated as "low transmittance of light at a wavelength of 400 nm".

[0121] [Yellow Degree (YI)] For the polyimide films obtained in each laminate obtained in the following examples and comparative examples, the transmittance of light with wavelengths of 200 nm to 800 nm was measured using a UV-Vis-NIR spectrophotometer ("V-650" manufactured by Nippon Spectrophotometer Co., Ltd.), and the yellowness (YI) of the polyimide film was calculated according to the formula described in JIS K7373-2006.

[0122] [Total light transmittance (TT)] For the polyimide films peeled off from each laminate obtained in the following examples and comparative examples, the total light transmittance (TT) was measured using an integrating sphere haze meter ("HM-150N" manufactured by Murakami Color Technology Research Institute Co., Ltd.) according to the method described in JIS K7361-1:1997.

[0123] [Haze] For the polyimide films peeled off from each laminate obtained in the following examples and comparative examples, the haze was measured using an integrating sphere haze meter ("HM-150N" manufactured by Murakami Color Technology Research Institute Co., Ltd.) according to the method described in JIS K7136-2000.

[0124] [Internal Stress] On a Corning glass substrate (material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) with pre-measured warpage, the polyimide compositions prepared in the following examples and comparative examples were coated using a spin coater. After heating in air at 120°C for 30 minutes, the substrate was heated at 430°C for 30 minutes under a nitrogen atmosphere to obtain a laminate with a polyimide film of 10 μm thickness on the glass substrate. To eliminate the influence of water absorption by the polyimide film, the laminate was dried at 120°C for 10 minutes, and then the warpage of the laminate under a nitrogen atmosphere at 25°C was measured using a thin film stress measuring device (FLX-2320-S manufactured by KLA-Tencor). Then, based on the warpage of the glass substrate and the warpage of the laminate before the formation of the polyimide film, the internal stress generated between the glass substrate and the polyimide film is calculated using the Stoney formula.

[0125] [1% weight reduction temperature (TD1)] The polyimide films obtained in the following examples and comparative examples (specifically, polyimide films sampled from each laminate at a weight of 10 mg) were used as test samples. A differential thermal-thermogravimetric analyzer (Hitachi High-Tech Science TG / DTA7200) was used, and the temperature was increased from 25°C to 650°C at a rate of 20°C / min under a nitrogen atmosphere. The weight of the sample at a test temperature of 150°C was used as a reference, and the test temperature at which the weight decreased by 1% relative to this reference was defined as the 1% weight reduction temperature (TD1). When TD1 was 500°C or higher, the heat resistance was evaluated as "excellent." On the other hand, when TD1 was less than 500°C, the heat resistance was evaluated as "poor."

[0126] [Glass transition temperature (Tg)] Polyimide films with a width of 3 mm and a length of 10 mm were sampled from each laminate obtained in the examples and comparative examples described below as samples for Tg determination. Using a thermal analysis apparatus (TMA / SS7100 manufactured by Hitachi High-Tech Science), a load of 98.0 mN was applied to the samples, and the temperature was increased from 20°C to 470°C at a rate of 10°C / min. The temperature was plotted against strain (elongation) to obtain a TMA curve. The temperature at the inflection point of the obtained TMA curve (the temperature corresponding to the peak in the differential curve of the TMA curve) was taken as the glass transition temperature (Tg).

[0127] <Production of Polyimide Film> The following describes the methods for preparing polyimide films (laminated structures) in the examples and comparative examples. Hereinafter, compounds and reagents will be referred to by the abbreviations below. Furthermore, the preparation of the polyamide compositions used in preparing the polyimide films was carried out under a nitrogen atmosphere. Also, the LUMO (calculated values ​​obtained using DFT) of each dianhydride used as a monomer is shown in Table 1, and the HOMO (calculated values ​​obtained using DFT) of each diamine used as a monomer is shown in Table 2. NMP: N-methyl-2-pyrrolidone NTCDA: 2,3,6,7-Naphthalenetetracarboxylic acid dianhydride PMDA: Pyromellitic dianhydride BPDA: 3,3',4,4'-Biphenyltetracarboxylic acid dianhydride BPAF: 9,9-bis(3,4-dicarboxyphenyl)piperidine ODPA: 4,4'-Oxyphthalic anhydride DODA: 4,4'-dioxophthalic anhydride SFDA: Spiro[11H-difurano[3,4-b:3',4'-i]𠮿 -11,9'-[9H][-1,3,7,9-tetraone] TFMB: 2,2'-bis(trifluoromethyl)benzidine BAAB: 4-Aminobenzoic acid 4-aminophenyl ester BAFL: 9,9-bis(4-aminophenyl) bacon 6FODA:2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether PDA: p-phenylenediamine PX-200: Hydroquinone poly(di-2,6-dimethyl) phosphate manufactured by Daihachi Chemical Industry Co., Ltd. TPPi: Triphenyl Phosphite

[0128] [Table 1] LUMO[eV] PMDA -4.32 NTCDA -3.80 BPDA -3.47 BPAF -3.19 ODPA -3.43 DODA -3.60 SFDA -3.24

[0129] [Table 2] HOMO[eV] PDA -5.02 TFMB -6.04 BAAB -5.63 BAFL -5.55 6FODA -5.94

[0130] [Example 1] 40.0 g of NMP was added as an organic solvent for polymerization to a 300 mL glass separable flask equipped with a stirrer with a stainless steel stirring rod and a nitrogen inlet tube. Then, while stirring the contents of the flask, 5.272 g of TFMB was added to the flask to dissolve it. Next, 3.973 g of NTCDA and 0.755 g of BPAF were added to the contents of the flask, and the mixture was stirred for 24 hours at 25°C to obtain a polyamide composition. The obtained polyamide composition was coated onto a glass substrate (manufactured by Corning Incorporated, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) using a spin coater. After heating in air at 120°C for 30 minutes, it was heated at 430°C for 30 minutes under a nitrogen atmosphere to obtain a laminate with a polyimide film of 10 μm thickness on the glass substrate (laminate of Example 1).

[0131] [Example 2] 40.0 g of NMP was added as an organic solvent for polymerization to a 300 mL glass separable flask equipped with a stirrer with a stainless steel stirring rod and a nitrogen inlet tube. Then, while stirring the contents of the flask, 5.272 g of TFMB was added to the flask to dissolve it. Next, 3.973 g of NTCDA and 0.755 g of BPAF were added to the contents of the flask, and the contents were stirred for 24 hours at 25°C. Then, TPPi, as a plasticizer, was added to the contents of the flask to obtain a polyacrylic acid composition. The amount of TPPi added was 1 part by weight relative to 100 parts by weight of polyacrylic acid in the contents of the flask. The obtained polyamide composition was coated onto a glass substrate (manufactured by Corning Incorporated, material: alkali-free glass, thickness: 0.7 mm, size: 100 mm × 100 mm) using a spin coater. After heating in air at 120°C for 30 minutes, it was heated at 430°C for 30 minutes under a nitrogen atmosphere to obtain a laminate with a polyimide film of 10 μm thickness on the glass substrate (laminate of Example 2).

[0132] [Examples 3-30 and Comparative Examples 1-7] Except that the acid dianhydride used and its feed ratio, and the diamine used and its feed ratio are set as shown in Tables 3 and 4, the laminates of Examples 3-6, 8, 10-27 and 29, and Comparative Examples 1-7 were obtained by the same method as in Example 1. Furthermore, except that the acid dianhydride used and its feed ratio, the diamine used and its feed ratio, and the type of plasticizer are set as shown in Tables 3 and 4, the laminates of Examples 7, 9, 28 and 30 were obtained by the same method as in Example 2. Moreover, for any of Examples 3-30 and Comparative Examples 1-7, the total mass of acid dianhydride used in preparing the polyamide composition was the same as in Examples 1 and 2. Also, for any of Examples 3-30 and Comparative Examples 1-7, the total mass of diamine used in preparing the polyamide composition was the same as in Examples 1 and 2.

[0133] Regarding Examples 1-30 and Comparative Examples 1-7, the monomers and plasticizers used are shown in Tables 3 and 4. Furthermore, in Tables 3 and 4, "-" indicates that the component was not used. Also, in Tables 3 and 4, the values ​​in the "Acid Dihydric Anhydride" column represent the content of each acid dianhydride relative to the total amount of acid dianhydride used (unit: moles%). In Tables 3 and 4, the values ​​in the "Diamine" column represent the content of each diamine relative to the total amount of diamine used (unit: moles%). In Tables 3 and 4, the values ​​in the "Plasticizer" column represent the amount of plasticizer relative to 100 parts by weight of polyamide (unit: parts by weight). Furthermore, for any of Examples 1-30 and Comparative Examples 1-7, the molar fraction of each residue of polyamide in the prepared polyamide composition is consistent with the molar fraction of each monomer (diamine and tetracarboxylic dianhydride) used in the synthesis of polyamide.

[0134] [Table 3] Acid dianhydride [molar percentage] Diamine [mol%] Plasticizer [parts by weight] NTCDA PMDA BPDA BPAF ODPA DODA SFDA TFMB BAAB BAFL 6FODA PDA PX-200 TPPi Example 1 90 - - 10 - - - 100 - - - - - - Example 2 90 - - 10 - - - 100 - - - - - 1 Example 3 80 - - 10 10 - - 100 - - - - - - Example 4 80 - - 16 - - 4 100 - - - - - - Example 5 75 - 15 10 - - - 100 - - - - - - Example 6 70 - 15 15 - - - 100 - - - - - - Example 7 70 - 15 15 - - - 100 - - - - - 1 Example 8 65 - 15 20 - - - 100 - - - - - - Example 9 65 - 15 20 - - - 100 - - - - 1 - Example 10 65 - 15 16 - 4 - 100 - - - - - - Example 11 65 - 15 16 - - 4 100 - - - - - - Example 12 60 - 30 10 - - - 100 - - - - - - Example 13 50 - 40 10 - - - 100 - - - - - - Example 14 40 - 50 10 - - - 100 - - - - - - Example 15 50 - 40 10 - - - 90 10 - - - - - Example 16 50 - 40 10 - - - 90 - 10 - - - - Example 17 50 - 40 10 - - - 90 - - 10 - - - Example 18 50 10 30 10 - - - 100 - - - - - - Example 19 5 - 90 5 - - - 100 - - - - - -

[0135] [Table 4] Acid dianhydride [molar percentage] Diamine [mol%] Plasticizer [parts by weight] NTCDA PMDA BPDA BPAF ODPA DODA SFDA TFMB BAAB BAFL 6FODA PDA PX-200 TPPi Example 20 50 - 50 - - - - 100 - - - - - - Example 21 80 - - - 20 - - 100 - - - - - - Example 22 70 - - - - - 30 100 - - - - - - Example 23 50 - - - - - 50 100 - - - - - - Example 24 70 - - 30 - - - 100 - - - - - - Example 25 50 - - 50 - - - 100 - - - - - - Example 26 20 - 50 - - - 30 100 - - - - - - Example 27 40 - 30 - - - 30 100 - - - - - - Example 28 40 - 30 - - - 30 100 - - - - - 1 Example 29 70 - 10 20 - - - 100 - - - - - - Example 30 70 - 10 20 - - - 100 - - - - - 1 Comparative Example 1 100 - - - - - - 100 - - - - - - Comparative Example 2 - 75 15 10 - - - 100 - - - - - - Comparative Example 3 50 - 50 - - - - twenty five - - - 75 - - Comparative Example 4 - 50 - - 50 - - 100 - - - - - - Comparative Example 5 50 - 50 - - - - 40 - - - 60 - - Comparative Example 6 - 70 - 30 - - - 100 - - - - - - Comparative Example 7 - 70 - - - - 30 100 - - - - - -

[0136] <Results of the physical property measurement> For each of Examples 1-30 and Comparative Examples 1-7, the results of the measurement of the average energy level difference and physical properties are shown in Table 5. Furthermore, in Table 5, "-" indicates that no measurement was performed.

[0137] [Table 5] Average energy level difference [eV] 400 nm transmittance [%] YI TT [%] Haze [%] Internal stress [MPa] TD1 [℃] Tg [℃] Example 1 2.30 40 12 86 0.8 -twenty two >500 >470 Example 2 2.30 41 11 87 0.7 -twenty three >500 >470 Example 3 2.34 40 10 85 0.5 3 >500 >470 Example 4 2.36 41 11 86 0.8 6 >500 >470 Example 5 2.35 41 10 85 0.6 -5 >500 >470 Example 6 2.38 44 9 86 0.6 4 >500 >470 Example 7 2.38 50 7 87 0.5 5 >500 >470 Example 8 2.41 49 7 86 0.5 16 >500 >470 Example 9 2.41 51 6 87 0.5 15 >500 >470 Example 10 2.36 40 11 85 0.6 3 >500 >470 Example 11 2.41 44 8 86 0.6 13 >500 >470 Example 12 2.40 50 6 86 0.4 8 >500 >470 Example 13 2.43 49 7 86 0.5 4 >500 >470 Example 14 2.47 48 5 87 0.4 14 >500 >470 Example 15 2.39 43 8 86 0.8 5 >500 415 Example 16 2.38 40 8 87 0.8 20 >500 >470 Example 17 2.42 48 7 87 0.4 14 >500 >470 Example 18 2.35 45 9 86 0.5 7 >500 >470 Example 19 2.57 59 4 87 0.6 29 >500 365 Example 20 2.41 47 8 86 0.8 -5 >500 >470 Example 21 2.31 41 12 85 0.5 1 >500 460 Example 22 2.41 50 8 87 0.6 -4 >500 >470 Example 23 2.52 56 7 87 0.5 15 >500 >470 Example 24 2.42 52 7 87 0.6 28 >500 >470 Example 25 2.55 62 5 88 0.4 35 >500 >470 Example 26 2.57 65 3 89 0.4 28 >500 >470 Example 27 2.51 52 8 87 0.4 18 >500 >470 Example 28 2.51 56 6 88 0.4 10 >500 >470 Example 29 2.40 47 8 86 0.5 16 >500 >470 Example 30 2.40 48 7 87 0.6 12 >500 >470 Comparative Example 1 2.24 36 14 84 1.1 -25 >500 >470 Comparative Example 2 1.96 32 10 87 0.3 7 >500 450 Comparative Example 3 1.64 0 36 78 0.4 -6 >500 >470 Comparative Example 4 2.17 0 149 - >10 41 >500 - Comparative Example 5 1.79 0 29 81 0.9 -8 >500 - Comparative Example 6 2.06 37 10 88 0.3 30 >500 - Comparative Example 7 2.04 35 10 87 0.2 12 >500 -

[0138] The polyamide compositions prepared in Examples 1-30 contain polyamides comprising one or more residues selected from the group consisting of BPDA residues, BPAF residues, ODPA residues, and SFDA residues, NTCDA residues, and TFMB residues. In the polyamide compositions prepared in Examples 1-30, the NTCDA residue content relative to the total amount of tetracarboxylic dianhydride residues is 5 mol% to 90 mol%. In the polyamide compositions prepared in Examples 1-30, the TFMB residue content relative to the total amount of diamine residues is 50 mol% or more.

[0139] As shown in Table 5, in Examples 1-30, the transmittance at 400 nm was over 40%. Therefore, the polyimides obtained in Examples 1-30 have high transmittance at 400 nm. In Examples 1-30, TD1 exceeded 500°C. Therefore, the polyimides obtained in Examples 1-30 have excellent heat resistance.

[0140] Regarding the polyamide in the polyamide composition prepared in Comparative Example 1, the content of NTCDA residues relative to the total amount of tetracarboxylic dianhydride residues exceeds 90 mol%. The polyamide in the polyamide compositions prepared in Comparative Examples 2, 4, 6, and 7 does not contain NTCDA residues. Regarding the polyamide in the polyamide compositions prepared in Comparative Examples 3 and 5, the content of TFMB residues relative to the total amount of diamine residues is less than 50 mol.

[0141] As shown in Table 5, the transmittance at 400 nm was less than 40% in Comparative Examples 1-7. Therefore, the transmittance of the polyimide obtained in Comparative Examples 1-7 at a wavelength of 400 nm is not high.

[0142] The above results demonstrate that, according to the present invention, it is possible to obtain polyimide with excellent heat resistance and high transmittance of light at a wavelength of 400 nm.

Claims

1. A polyamide having a tetracarboxylic dianhydride residue and a diamine residue, wherein the tetracarboxylic dianhydride residue comprises one or more residues selected from the group consisting of 9,9-bis(3,4-dicarboxyphenyl)furan dianhydride residues, spiro[11H-difurano[3,4-b:3',4'-i]-11,9'-[9H]furan]-1,3,7,9-tetraone residues, and 2,3,6,7-naphthalenetetracarboxylic dianhydride residues, wherein the diamine residue comprises a 2,2'-bis(trifluoromethyl)benzidine residue, wherein the content of the 2,3,6,7-naphthalenetetracarboxylic dianhydride residue relative to the total amount of the tetracarboxylic dianhydride residue is 5 mol% or more and 90 mol% or less, and the content of the 2,2'-bis(trifluoromethyl)benzidine residue relative to the total amount of the diamine residue is 50 mol% or more.

2. The polyamide of claim 1, wherein when the diamine residues include diamine residues that are different from the 2,2'-bis(trifluoromethyl)benzidine residues, the diamine residues that are different from the 2,2'-bis(trifluoromethyl)benzidine residues are derived from diamine residues with a highest occupied orbital energy level of -5.20 eV or lower.

3. The polyamide of claim 2, wherein the diamine residue different from the 2,2'-bis(trifluoromethyl)benzidine residue is selected from one or more residues in the group consisting of 4-aminobenzoic acid 4-aminophenyl ester residue, 9,9-bis(4-aminophenyl) benzoate residue, and 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether residue.

4. The polyamide of claim 2, wherein the content of diamine residues different from the above-mentioned 2,2'-bis(trifluoromethyl)benzidine residues is 1 mol% to 50 mol% relative to the total amount of the above-mentioned diamine residues.

5. The polyamide of claim 4, wherein the tetracarboxylic dianhydride residue further comprises 3,3',4,4'-biphenyltetracarboxylic dianhydride residue, wherein the content of the 3,3',4,4'-biphenyltetracarboxylic dianhydride residue relative to the total amount of the tetracarboxylic dianhydride residue is 30 mol% or more and 50 mol% or less.

6. The polyamide of claim 1, wherein the difference between the average value of the lowest unoccupied orbital energy level of the tetracarboxylic dianhydride forming the above-mentioned tetracarboxylic dianhydride residue and the average value of the highest occupied orbital energy level of the diamine forming the above-mentioned diamine residue is 2.25 eV or more.

7. A polyamide composition comprising the polyamide as claimed in claim 1 and an organic solvent.

8. The polyamide composition of claim 7, further comprising a plasticizer.

9. The polyamide composition of claim 8, wherein the amount of the plasticizer is 0.001 parts by weight or more and 10 parts by weight or less relative to 100 parts by weight of the polyamide.

10. The polyamide composition of claim 8, wherein the plasticizer comprises phosphorus.

11. A polyimide, which is a polyimide of the polyamide as claimed in claim 1.

12. The polyimide of claim 11 has a 1% weight reduction temperature of 500°C or higher.

13. A polyimide film comprising the polyimide of claim 11.

14. The polyimide film of claim 13 has a transmittance of 40% or more for light at a wavelength of 400 nm.

15. The polyimide film of claim 13 has a haze of less than 1.0%.

16. A laminate having a support and a polyimide film as claimed in claim 13.

17. A method for manufacturing a laminate comprising a support and a polyimide film, wherein a coating film comprising the polyamide composition of claim 7 is formed by coating the polyamide composition of claim 7 onto the support, and the polyamide is amide-imidized by heating the coating film.

18. An electronic device having a polyimide film as claimed in claim 13 and electronic components disposed on the polyimide film.

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